(1) Summary of the Invention
The present invention relates to a method and compositions for inhibiting oxidation in various materials, particularly lipids and most particularly in foods. In particular, the present invention uses a tart cherry natural extract containing a mixture of anthocyanins to accomplish the inhibition.
(2) Description of Related Art
Prunus Cerasus L. (Rosacease), cv. MONTMORENCY is the major tart cherry commercially grown in the United States. An artificial red dye is frequently added to MONTMORENCY cherry food products to enhance its low natural red color. In order to challenge the MONTMORENCY monoculture, a new cultivar, BALATON tart cherry (Ujferbertoi furtos), was introduced into the United States in 1984, and has been tested in Michigan, Utah, and Wisconsin. BALATON produces fruits darker than MONTMORENCY.
Colorants like anthocyanins were regarded as the index of quality in tart cherries. Most importantly, recent results showed that anthocyanins such as cyanidin-3-glucoside have strong antioxidant activities (Tsuda, T., et al, J. Agric. Food Chem. 42:2407-2410 (1994)). The addition of antioxidants is one of the popular methods to increase the shelf life of food products which is thought to be associated with lipid peroxidation. Natural antioxidants may play an important role in the prevention of carcinogenesis. Dietary antioxidants may be effective against the preoxidative damage in living systems (Halliwell, B. and J. M. C. Gutteridge, Free radicals in biology and medicine. Oxford University Press, New York 416-494 (1989); Osawa, T., et al, Role of dietary antioxidants in protection against oxidative damage. In antimutagenesis and anticarcinogenesis Mechanisms; Kuroda, Y.; Shankel, D. M., Waters, M. D., Eds.; Plenum Publishing. New York 139-153 (1990)).
Early studies have showed that MONTMORENCY cherry contains cyanidin-3-gentiobioside and cyanidin-3-rutinoside (Li, K. C., et al., J. Am. Chem. Soc. 78:979-980 (1956)). Cyanidin-3-glucosylrutinoside was also found in six out of the seven sour cherry varieties (Harborne, J. B., et al., Phytochemistry 3:453-463 (1964)). Dekazos (Dekazos, E.D., J. Food Sci. 35:237-241 (1970)) reported anthocyanin pigments in MONTMORENCY cherry as peonidin-3-rutinoside, peonidin and cyanidin along withcyanidin-3-sophoroside, cyanidin-3-rutinoside and cyanidin-3-glucoside. However, cyanidin-3-glucosylrutinoside as well as cyanidin-3-glucoside, cyanidin-3-sophoroside and cyanidin-3-rutinoside were identified as main pigments in sour cherries. Using HPLC retention values, Chandra et al (Chandra, A., et al., J. Agric. Food Chem. 40:967-969 (1992)) reported that cyanidin-3-sophoroside and cyanidin-3-glucoside were the major and minor anthocyanins, respectively, in Michigan grown MONTMORENCY cherry. Similarly, cyanidin-3-xylosylrutinoside was detected as a minor pigment in MONTMORENCY cherry (Shrikhande, A. J. and F. J. Francis, J. Food Sci. 38:649-651 (1973)).
U.S. Pat. No. 5,503,867 to Pleva describes the use of whole ground cherries and oat bran in ground meat. The amount of cherries used is 10 to 15% by weight and the oat bran is believed to be added to compensate for the juice in the cherries. In any event, the cherries definitely contribute a flavor to the meat.
There is a need for natural antioxidants for use, particularly in foods and other materials containing oxidizable compounds. Lipids in meats are particularly prone to oxidation and contribute to rancidity in cooked or uncooked foods and natural lipid products for a variety of uses.